Air-thrusting water craft serve unique purposes along water courses that are difficult to navigate by standard water vehicles. The air-thrusting mechanism of these water craft eliminate the need for water guided rudders, centerboards, and water propulsion impellers. In swamps and other shallow water pathways, such projections often foul upon grasses and underwater vegetation, making navigation hazardous and difficult.
Air boats are also known for their ability to traverse through shallow, intricate, and serpentine water courses, by reason of their minimum hull depth below the water line, and their general maneuverability.
The shallow hulls which lack rudder and centerboard, however, make these type of craft hard to handle and control. In operation, such craft have been found to be unstable and subject to capsizing and swamping in rough water, rapids and broken ice. Furthermore, most prior structures lack sufficient flotation and are not readily freed quickly when the craft is run aground in shallow water, muck, mud, ice, snow, or dry land. Movements are generally imprecise. The boats tend to slide sideways in turns and maneuvers. Cross winds tend to push them off course, and spray is kicked up during sharp turns by virtue of the side thrusting.
Moreover, conventional air boats have steering systems--often with "stick" controls--that return to center position, self-straightening due to propwash when the pilot releases control of the stick. In many situations, however, this tendency is neither desired nor especially safe, as control of the boat is comprised.
The center of gravity of conventional air boats is high, due to the height of the propeller axis and engine mount above the boat deck. The engine and propeller usually sit several feet above the deck surface. The high center of gravity exacerbates the sloppy handling and control. Another problem is that overall prior air boat height, generally 8'-10', restricts boat usage and storage in low clearance areas. In addition, the general smoothness and shallowness of the hull provides little resistance to side forces, which act to propel the craft sideways. It is not unusual for such conventional air boats to have long turning radii.
The flexibility of the hulls of the air boats also causes fatigue, resulting in cracks and structural failure. Conventional air boat polymer bottom design, using one or more large pieces below the hull, can tear apart and scoop surface material, which immobilizes or severely slows the craft.
The current invention endeavors to provide an air boat that generally eliminates or substantially reduces all of the aforementioned disadvantages. The present invention seeks to provide an air boat that is precisely maneuverable, has improved handling, and which is less influenced by side thrusting forces. The air boat's light weight aids the pilot in freeing the boat if it runs aground. The boat itself has sufficient structural integrity to survive impacts over a long period of time.
The invention features an air-thrusted craft that has an improved hull, deck, and thrusting design. The deck is constructed with rigid formed aluminum channels and members or side ribs that reduce structural flexibility of the hull during turns and maneuvers. The bottom of the hull is provided with a plurality of substantially parallel channels, which greatly reduce sideways slide, and which reduce spray kick-up during sharp turns. Since the dual steering fins are capable of moving more than 45.degree., the boat has a very short turning radius.
The motor and multi-blade propeller of the thrusting mechanism are lightweight, and are mounted in a smaller cage. In fact, the motor mount uses the boat hull itself for its base structural element and the cage is set lower to the deck surface. This greatly improves the center of gravity, by lowering it, relative to the water line of the boat. Hollow panels disposed in the hull are filled with rigid foam to improve buoyancy in case of partial submergence. Hull parts are welded instead of riveted, to provide a uniformly contiguous, frameless design. The hull bottom is coated with polyethylene or PTFE to improve hull water friction, resistance to abrasion, and freedom from freezing to ice.
It is an object of this invention to provide an improved air boat.
It is another object of the invention to provide an air-thrusted water craft having improved handling and control.
Another object of this invention is to provide a novel surface craft adapted to be propelled on land, marsh, ice, snow and rough water surfaces.
A further object of this invention is to provide a novel surface craft having increased stability and safety when operating in rough water and rapids.
A further object of this invention is to provide a novel surface craft which is light and slippery enough to be freed quickly when the craft has run aground in shallow water, muck, mud, snow, ice or dry land.
An additional object of the present invention is to provide an air boat with a relatively short overall boat height to allow the boat to access low clearance areas.
Another object of this invention is to adhere multiple strips of a high strength polymer to the bottom of the hull such that damage to the polymer does not immobilize or significantly slow the craft.
A further object of this invention is to provide sufficient flotation such that the craft floats level when filled or partially filled with water.
A still further object of this invention is to provide an air boat with a relatively low center of gravity to provide better maneuverability, compared to prior conventional air boat structures.
It is a further object of this invention to provide an air boat, the hull of which comprises an overall one-frame construction for increasing usable area and decreasing weight without sacrificing material strength.
It is yet another object of the invention to provide an air boat having a fold-down safety cage.
It is yet another object of the invention to provide an air boat having one or more steerable fins connected to a non-feedback steering mechanism.
It is yet another object of the invention to provide an air boat having a steering mechanism incorporated in universally familiar controls, which steering mechanism allows the boat to turn in a short turning radius.
It is yet another object of the invention to provide an air boat being fabricated of ultralight components and having improved buoyancy characteristics.